Hi all
I bought an MP PIR sensor on eBay (
It has its owns battery, and works well when working on battery, but when I plug it in (I need it for longer time that the battery lasts), then it will contact me quite often. It uses a USB mini charger.
We have no idea what can cause this, so we can only guess. Any suggestions?
Ahh power supply seems like the obvious answer. Try another one, or hack and filter the one you have.
George H.
Some PIRs are not well shielded against electrostatic fields. If the power supply is class 2 and there are y-capacitors from the mains to the output side then the PIR could be flapping around at half the mains voltage, plus a bunch of switcher hash, and that could cause a strong electric field around the PIR. If that is the case then connecting the negative terminal of the power supply to earth can improve things.
I added and extension with an inductor and a capacitor and it works. It will take a few days to see whether it is stable.
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